A Randomized Comparison of Methods of Selecting Narrowband UV-B Starting Dose to Treat Chronic Psoriasis

Robert S. Dawe, Heather M. Cameron, Susan Yule, Sally H. Ibbotson, Harry H. Moseley, James Ferguson

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    Abstract

    Objectives: To compare narrowband UV-B (TL-01 lamp) phototherapy for psoriasis with individual patient starting doses based on minimal erythemal dose (MED) determination vs a standard fixed starting dose and to compare the efficacy of 70% of MED vs 50% of MED starting dose regimens.

    Design: Single-center, randomized, double-blind, clinical trial.

    Setting: Department of Dermatology, Ninewells Hospital and Medical School, Dundee, Scotland.

    Patients: A total of 210 adult patients (207 of skin phototypes I to III) referred for narrowband UV-Bto treat chronic psoriasis. The study was designed to have 90% powerto detect a difference of 3 or more treatments to clearance and/or minimal residual activity (MRA) between groups.

    Interventions: Narrowband UV-Bphototherapy was given according to 3 standard regimens, differing only by starting dose selection method. The randomly allocated starting doses were (1) a fixed starting dose, (2) 70% of individual MED, and (3) 50% of individual MED. All patients were MED tested to ensure blinding and for safety reasons.

    Main Outcome Measures: The number of treatments to clearance and/or MRA of psoriasis was the primary efficacy outcome measure, with changes in Psoriasis Area and Severity Index and Psoriasis Disability Index scores as secondary measures. Adverse effects were recorded.

    Results: There were no significant differences in the number of treatments to clearance and/or MRA across all 3 groups or in the percentages achieving clearance in each group. More uncomfortable erythemas occurred in the 50% of MED starting dose group (39%) than in the 70% of MED starting dose group (24%) or the fixed starting dose group (24%) (P=.07).

    Conclusions: The methods of determining the starting dose in this predominantly skin phototype I and II population, treated 3 times weekly, with a 20% followed by 10% incremental reduction in dose, did not significantly influence the effectiveness of treatment. Had there been a clinically important difference in efficacy, we would have expected to identify this. Thus, basing starting dose on individual MED assessments may not influence the treatment's efficacy in a skin phototype I to III population, although it remains important for patient safety. It remains possible that in populations containing individuals with a broader range of erythemal sensitivity, basing the starting dose on MED testing could have an important impact on treatment effectiveness.

    Original languageEnglish
    Pages (from-to)168-174
    Number of pages7
    JournalArchives of dermatology
    Volume147
    Issue number2
    DOIs
    Publication statusPublished - Feb 2011

    Keywords

    • CHRONIC PLAQUE PSORIASIS
    • ULTRAVIOLET-B
    • 3 TIMES
    • PHOTOTHERAPY
    • ERYTHEMA
    • DISABILITY
    • REGIMENS
    • THERAPY
    • IMPACT
    • INDEX

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